It's easier not to ask too many questions about pedophilia. The questions make you blush; some of the answers make your skin crawl. But it seems that almost daily we see another grown man tell his story and weep, suddenly becoming the terrified kid he once was. All the revelations, all spilling out at once, have created a fog: Why are there so many people who want to molest children? How can we stop them? Are we overreacting?

The flood of reports could almost make you think that everyone who sexually abuses a child is a Roman Catholic priest. In fact, the perpetrators are a disturbingly diverse lot. There's the Chicago-area nurse who molested up to 18 patients, including a 9-year-old girl who had suffered a brain aneurysm and later died. There's the 33-year-old Nevada day-care worker who committed hundreds of sexual acts on at least nine children, mostly ages 2 and 3--and videotaped them. Some of the most heartbreaking allegations involve the American Boychoir School, a top choral program in Princeton, N.J. More than a dozen alumni from the 1960s to the '80s now say they were sexually abused by at least 11 former staff members. Says John Hardwicke Jr., 44, who claims he was raped repeatedly at the boarding school: "What we all seemed to share was this sense of darkness."

But it is possible to cast light on this difficult subject. Though researchers have many unanswered questions about child sexual abusers, a serious, if small, academic field is devoted to understanding and preventing their behavior--and to comprehending its effects on their victims. Such work can require cold-eyed questions that poke around the edges of our darkest taboos. At the outset, it's important to note that news accounts often conflate two phenomena: pedophilia and child sexual abuse. According to Dr. Fred Berlin, a Johns Hopkins University professor who founded the National Institute for the Study, Prevention and Treatment of Sexual Trauma in Baltimore, Md., pedophilia is a distinct sexual orientation marked by persistent, sometimes exclusive, attraction to prepubescent children. Dr. John Bradford, a University of Ottawa psychiatrist who has spent 23 years studying pedophilia--which is listed as an illness in the manual psychiatrists use to make diagnoses--estimates its prevalence at maybe 4% of the population. (Those attracted to teenagers are sometimes said to suffer "ephebophilia," but perhaps because so many youth-obsessed Americans would qualify, psychiatrists don't classify ephebophilia as an illness.)

A psychiatric diagnosis of pedophilia merely indicates one's desires; not all pedophiles act on their urges and actually commit child sexual abuse. Plenty of sexual abuse of kids is committed by ordinary people not generally attracted to children. That's one reason the incidence of child sexual abuse is so maddeningly high. A Department of Health and Human Services study estimates that victimizers sexually abused 93,000 U.S. children in 1999 (the latest year for which data are available). But there is some good news. Last year the Department of Justice reported that the number of substantiated cases of child sexual abuse has been decreasing, from a peak of nearly 150,000 in 1992 to about 104,000 in 1998--a drop of almost one-third. The authors say vigorous incarceration of offenders over the past few years may be partly responsible.

But if we have punished our way out of the problem somewhat, we still don't have a long-term solution. Many people assume that not only priests but also teachers, Boy Scout leaders and other adults who work with kids are responsible for most child sexual abuse, but that's a misconception. Half of child sexual abusers are the parents of the victims; other relatives commit 18% of the offenses. And the sad truth is that preventing incest is nearly impossible. Less than one-third of perpetrators know their victims from outside the home. But non-family abusers may be easier to pick out--many are adults who shower uncommon attention on children--and thus easier to stop.

Although news reports focus on horrific serial offenders, experts say it's possible, with treatment, to prevent pedophiles from abusing kids. States have incarcerated many child sexual abusers, but most eventually get out (average sentence: 11 years). Active pedophiles who find their way into the few treatment programs around the country turn out to be less of a risk than those who are locked up for a while and released.

Berlin runs one of the largest such programs in the nation. Since 1991 hundreds of pedophiles have gone to the creaky Victorian building that houses his clinic. Berlin sees their condition as similar to alcoholism--incurable but treatable--and some of his methods sound similar to those of Alcoholics Anonymous. The pedophiles must admit their urges and confront them in group therapy. Counselors help them restructure their lives so that they don't come into contact with children. Berlin prescribes medication to reduce sex drives for the 30% of his patients who don't respond to nondrug therapy.